<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    var str = 'string';
    var obj = new Date();
    var obj2 = null;
    var fun = function () {
      console.log('ddd');
    }
    var und;
    var boo = true;
    var test = /\.js/;

    console.log(typeof 10);     // number
    console.log(typeof str);    // string
    console.log(typeof obj);    // object
    console.log(typeof obj2);   // object
    console.log(typeof fun);    // function
    console.log(typeof boo);    // boolean
    console.log(typeof und);    // undefined
    console.log(test);          // /\.js/
    console.log(typeof test);   // object
  </script>
</body>
</html>